EEPROMs are currently read in blocks of 16 bytes, but the em2800 is limited
to 4 bytes per read. All other chip variants support reading of max. 64 bytes
at once (according to the em258x datasheet; also verified with em2710, em2882,
and em28174).
Since em2800_i2c_recv_bytes() has been fixed to return with -EOPNOTSUPP when
more than 4 bytes are requested, EEPROM reading with this chip is broken.
It was actually broken before that change, too, it just didn't throw an error
because the i2c adapter silently returned trash data (for all reads >1 byte !).
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
- do not pass USB specific error codes to userspace/i2c-subsystem
- unify the returned error codes and make them compliant with
the i2c subsystem spec
- check number of actually transferred bytes (via USB) everywehere
- fix/improve debug messages
- improve code comments
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
I2C_FUNC_SMBUS_EMUL includes flag I2C_FUNC_SMBUS_WRITE_BLOCK_DATA which signals
that up to 31 data bytes can be written to the ic2 client.
But the EM2800 supports only i2c messages with max. 4 data bytes.
I2C_FUNC_IC2 should be set if a master_xfer function pointer is provided in
struct i2c_algorithm.
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Function em2800_i2c_recv_bytes() has 2 severe bugs:
1) It does not wait for the i2c read to complete before reading the received message content from the bridge registers.
2) Reading more than 1 byte doesn't work
The former can result in data corruption, the latter always does.
The rewritten code also superseds the content of function
em2800_i2c_check_for_device().
Tested with device "Terratec Cinergy 200 USB".
[mchehab@redhat.com: Fix CodingStyle issues]
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The em2800 can transfer up to 4 bytes per i2c message.
All other em25xx/em27xx/28xx chips can transfer at least 64 bytes per message.
I2C adapters should never split messages transferred via the I2C subsystem
into multiple message transfers, because the result will almost always NOT be
the same as when the whole data is transferred to the I2C client in a single
message.
If the message size exceeds the capabilities of the I2C adapter, -EOPNOTSUPP
should be returned.
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Rename all USB drivers with their own directory under
drivers/media/video into drivers/media/usb and update the
building system.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-08-15 16:25:07 -03:00
Renamed from drivers/media/video/em28xx/em28xx-i2c.c (Browse further)
